1. (Industrial useful field)
This invention relates to a fastening method of friction facing for clutch disc assembly suitable mainly for a dry automobile clutch.
2. (Prior art)
A conventional clutch disc assembly generally has a construction as illustrated in FIG. 5. Namely, in FIG. 5, 1 is a spline hub, 2 is a clutch plate, 3 is a cushioning plate, and 4 and 4' are friction facings. The spline hub 1 spline fits in a main drive shaft (having a center axis 5) forming an input shaft of a transmission, and integrally has a hub flange 7. The clutch plate 2 is fastened to this hub flange 7 by means of a rivet 8, the cushioning plate 3 is rigidly fixed to an outer peripheral part of the clutch plate 2 by means of a rivet 9, and the facings 4 and 4' are fastened to this cushioning plate 3 by means of a facing rivet 10.
An engine torque is generally transmitted from a flywheel (not shown) through a pressure plate (not shown), the friction facings 4 and 4', the clutch plate 2 and the spline hub 1 to the main drive shaft 5.
3. (Problem of the prior art)
In the above conventional construction wherein the facing rivet 10 is used for fastening the friction facings 4 and 4' to the cushioning plate 3, there was a problem that effective wear clearances of the friction facings 4 and 4' was considerably decreased due to the facing rivet to be installed. Therefore, even in the conventional embodiment, such a method was employed that the friction rivet 10 was disused and the friction facings 4 and 4' were heated and vulcanized by using a heating press system to unite the friction facing 4 with the friction facing 4' and at the same time to fasten the friction facings 4 and 4' to the cushioning plate 3 for the purpose of increasing the effective wear clearance of the friction facings 4 and 4'.
In the above system for fastening the friction facings 4 and 4', however, the friction facings 4 and 4' temporarily formed on the both sides of the cushioning plate 3 were fludic, and moreover such a problem was subject to be encountered that weight compositions of the friction facings 4 and 4' were apt to disperse so that thicknesses of the friction facing 4 and the friction facing 4' formed on both sides of the cushioning plate 3 were hard to made equal and a large difference was produced between the effective wear clearance of the friction plate 4 and that of the friction facing 4' on both sides of the cushioning plate 3.
4. (Object of the invention)
An object of this invention is to solve the above problem of the conventional embodiment. In order to accomplish the above object of this invention; in a fastening method of friction facing for clutch disc assembly wherein a clutch plate is fixed to a spline hub and friction facings are fastened to an outer peripheral part of said clutch plate through a cushioning plate; projections which are able to directly hold said cushioning plate in a sandwiching manner, are formed on a mold for forming said friction facings, the friction facings are formed into desired shapes within said mold and said friction facings are always fastened to said cushioning plate correctly by providing a correct holding position of said cushioning plate by means of the mold while heating and pressing said mold.